<?php

declare(strict_types=1);

namespace App\Mail;

use App\Form\FormSchema;

/**
 * Formats raw submission data into human-readable label/value pairs,
 * respecting visibility conditions and field types from the form schema.
 */
final class SubmissionFormatter
{
    private FormSchema $schema;

    public function __construct(FormSchema $schema)
    {
        $this->schema = $schema;
    }

    /**
     * @param array<string, mixed> $submission
     * @return array<int, array{title: string, fields: array<int, array{label: string, value: string}>}>
     */
    public function formatSteps(array $submission): array
    {
        $formData = (array) ($submission['form_data'] ?? []);
        $formData['is_minor'] = $this->deriveIsMinor($formData);
        $submissionEmail = trim((string) ($submission['email'] ?? ''));
        $result = [];

        foreach ($this->schema->getSteps() as $step) {
            $title = (string) ($step['title'] ?? '');
            $fields = [];

            foreach (($step['fields'] ?? []) as $fieldDef) {
                $key = (string) ($fieldDef['key'] ?? '');
                $type = (string) ($fieldDef['type'] ?? 'text');

                if ($key === '' || $type === 'file') {
                    continue;
                }
                if (!$this->isVisible($fieldDef, $formData)) {
                    continue;
                }

                $raw = $formData[$key] ?? null;
                if ($raw === null || $raw === '' || $raw === []) {
                    continue;
                }

                $label = (string) ($fieldDef['label'] ?? $key);
                $value = $this->formatValue($raw, $fieldDef);

                $fields[] = ['label' => $label, 'value' => $value];
            }

            if ($this->isPersonalDataStep($title) && $submissionEmail !== '' && !$this->hasEmailField($fields)) {
                $fields[] = ['label' => 'E-Mail', 'value' => $submissionEmail];
            }

            if ($fields !== []) {
                $result[] = ['title' => $title, 'fields' => $fields];
            }
        }

        return $result;
    }

    /**
     * @param array<string, mixed> $submission
     * @return array<int, array{label: string, files: array<int, string>}>
     */
    public function formatUploads(array $submission): array
    {
        $uploads = (array) ($submission['uploads'] ?? []);
        $uploadFields = $this->schema->getUploadFields();
        $result = [];

        foreach ($uploadFields as $key => $fieldDef) {
            $files = $uploads[$key] ?? [];
            if (!is_array($files) || $files === []) {
                continue;
            }

            $label = (string) ($fieldDef['label'] ?? $key);
            $names = [];
            foreach ($files as $file) {
                if (is_array($file)) {
                    $names[] = (string) ($file['original_filename'] ?? 'Datei');
                }
            }

            if ($names !== []) {
                $result[] = ['label' => $label, 'files' => $names];
            }
        }

        return $result;
    }

    /** @param array<string, mixed> $fieldDef */
    private function formatValue(mixed $raw, array $fieldDef): string
    {
        $type = (string) ($fieldDef['type'] ?? 'text');

        if ($type === 'date' && is_string($raw)) {
            return $this->formatDate($raw);
        }
        if ($type === 'checkbox') {
            return ((string) $raw === '1' || $raw === true) ? 'Ja' : 'Nein';
        }
        if ($type === 'select' && is_string($raw)) {
            return $this->resolveSelectLabel($raw, $fieldDef);
        }
        if ($type === 'table' && is_array($raw)) {
            return $this->formatTable($raw, $fieldDef);
        }
        if (is_scalar($raw)) {
            return (string) $raw;
        }

        return json_encode($raw, JSON_UNESCAPED_UNICODE) ?: '';
    }

    private function formatDate(string $value): string
    {
        $ts = strtotime($value);
        if ($ts === false) {
            return $value;
        }
        return date('d.m.Y', $ts);
    }

    /** @param array<string, mixed> $fieldDef */
    private function resolveSelectLabel(string $value, array $fieldDef): string
    {
        foreach (($fieldDef['options'] ?? []) as $opt) {
            if (is_array($opt) && (string) ($opt['value'] ?? '') === $value) {
                return (string) ($opt['label'] ?? $value);
            }
        }
        return $value;
    }

    /** @param array<string, mixed> $fieldDef */
    private function formatTable(array $rows, array $fieldDef): string
    {
        $columns = $fieldDef['columns'] ?? [];
        if (!is_array($columns) || $columns === []) {
            return '';
        }

        $lines = [];
        foreach ($rows as $row) {
            if (!is_array($row)) {
                continue;
            }
            $cells = [];
            $hasContent = false;
            foreach ($columns as $i => $col) {
                $cellValue = (string) ($row[$i] ?? '');
                $colType = (string) ($col['type'] ?? 'text');
                if ($colType === 'date' && $cellValue !== '') {
                    $cellValue = $this->formatDate($cellValue);
                }
                if ($cellValue !== '') {
                    $hasContent = true;
                }
                $colLabel = (string) ($col['label'] ?? '');
                $cells[] = $colLabel . ': ' . $cellValue;
            }
            if ($hasContent) {
                $lines[] = implode(' | ', $cells);
            }
        }

        return implode("\n", $lines);
    }

    /** @param array<string, mixed> $fieldDef */
    private function isVisible(array $fieldDef, array $formData): bool
    {
        if (isset($fieldDef['visible_if'])) {
            $cond = $fieldDef['visible_if'];
            $field = (string) ($cond['field'] ?? '');
            $expected = (string) ($cond['equals'] ?? '');
            $actual = (string) ($formData[$field] ?? '');
            if ($actual !== $expected) {
                return false;
            }
        }

        if (isset($fieldDef['hidden_if'])) {
            $cond = $fieldDef['hidden_if'];
            $field = (string) ($cond['field'] ?? '');
            $expected = (string) ($cond['equals'] ?? '');
            $actual = (string) ($formData[$field] ?? '');
            if ($actual === $expected) {
                return false;
            }
        }

        return true;
    }

    private function isPersonalDataStep(string $title): bool
    {
        return trim($title) === 'Persönliche Daten';
    }

    /** @param array<int, array{label: string, value: string}> $fields */
    private function hasEmailField(array $fields): bool
    {
        foreach ($fields as $field) {
            if (strtolower(trim((string) ($field['label'] ?? ''))) === 'e-mail') {
                return true;
            }
        }

        return false;
    }

    /** @param array<string, mixed> $formData */
    private function deriveIsMinor(array $formData): string
    {
        $birthdate = trim((string) ($formData['geburtsdatum'] ?? ''));
        if ($birthdate === '') {
            return '0';
        }

        $date = \DateTimeImmutable::createFromFormat('!Y-m-d', $birthdate);
        if (!$date || $date->format('Y-m-d') !== $birthdate) {
            return '0';
        }

        $today = new \DateTimeImmutable('today');
        if ($date > $today) {
            return '0';
        }

        return $date->diff($today)->y < 18 ? '1' : '0';
    }
}